VIENNA, Dec 5: UN atomic agency chief Mohamed ElBaradei weighed into the debate on whether the IAEA has the tools it needs to investigate Iran's nuclear programme when he said his agency had good access to suspicious sites.

"We follow on every piece of information that can give us an indication that there might be undeclared nuclear materials in Iran," ElBaradei said in an interview on Saturday.

ElBaradei's International Atomic Energy Agency (IAEA) is mandated under safeguards agreements from the nuclear Non Proliferation Treaty (NPT) to verify that all nuclear material in a country is declared and not being diverted for nuclear weapons purposes, as the United States claims is the case in Iran.

An IAEA board of governors resolution on Iran last week had failed to give the agency the "unrestricted access" in the Islamic Republic which nations like the United States say is needed if the IAEA is to resolve the Iranian nuclear question.

ElBaradei said the issue has been raised that "we do not have the authority to go everywhere" but he said this was a "non-issue because we have received access to every facility we asked for in Iran."

The IAEA goes beyond NPT accords in what it calls "transparency visits," when it asks Iran as a confidence-building measure to allow it to inspect sites, even if the agency does not have a suspicion of nuclear material at these places, ElBaradei said.

At the only site where the IAEA has asked to and has not yet gone, the Parchin military base where weapons work is suspected: "I have every reason to expect that Iran will allow us to go," ElBaradei said. But diplomats insist there are problems since the IAEA mandate "is to track nuclear equipment and nuclear material," not weapons, the diplomat said. This limited access is spelled out in the Additional Protocol to the NPT, a protocol which actually was drawn up in 1997 to give IAEA inspectors wider powers.

The powers fall far short of unrestricted access, said David Albright of the Washington think tank the Insitute for Science and International Security. Albright said South Africa and Libya, two states which have dismantled their nuclear weapons programs, had given the IAEA access even to sites involved in testing or development but where there was no atomic material.

A diplomat close to the agency said the IAEA's legal authority was "quite limited when you get into the area of nuclear weapons related activity" since actual nuclear material may not be present.

Another diplomat said the IAEA seemed to be saying that when it comes to tracing weapons work "the guidelines it is under make it impossible for the agency to do its job."

In any case, things can move slowly, and critics say this gives Iran time to hide things. But ElBaradei said "frankly the easiest thing to look for is nuclear material because of the signature," which the IAEA finds with environmental sampling swipes.

At the Kalaye workshop in Tehran, the IAEA had found tiny traces of enriched urnaium, even after the site had been re-painted. But at another suspected site in Tehran, Lavizan-Shian, no traces of radiation were found after the Iranians tore down buildings and ripped up topsoil, although there was no proof radioactive material had been there before these changes.

As for Parchin, US officials have said the Iranians may be testing there "high-explosive shaped charges with an inert core of depleted uranium" as a dry test for how a bomb with fissile material would work. But "the obstacles increase when one is trying to visit a military site," a diplomat said. -AFP